Status: 5th year graduate student
Research Area: Kinetics and Catalysis, Surface Science, Computational Chemistry, Fuel cell applications, Modeling
Hometown: Lucknow, India
Undergraduate Studies: Birla Institute of Technology and Science (BITS-Pilani), India
Research Summary:
Results from recent experimental studies have shown that supported gold catalysts hold strong promise for a number of low temperature reactions. Of particular interest are the application of Au for the low temperature water-gas shift (WGS) reaction and the preferential oxidation of CO in the presence of H2 (PROX). WGS is an important step in the production of H2 via the steam reforming of hydrocarbons and PROX is a key reaction for feeding low temperature fuel cells with clean hydrogen streams since the PEM fuel cell anodes get poisoned even by low levels (ppm) of CO. The enhanced activity of Au catalysts for these reactions at low temperatures still remains controversial.
We have carried out systematic studies of the elementary steps involved in the WGS reaction on supported Au particles and in the PROX reaction on Au, Cu and Pt surfaces. Density functional theory (DFT) is used to calculate thermo chemical and kinetic parameters (including energetics and frequency factors) of the relevant elementary steps of WGS and PROX reactions. This information is then combined with experiments and detailed microkinetic modeling to derive mechanistic insights about the nature of the active site, reaction orders, and surface coverages.
-in collaboration with-
Mavrikakis Group
Publications:
S. Kandoi, J. Greeley, M. A. Sanchez-Castillo, S. T. Evans, A. A. Gokhale, J.A. Dumesic, and M. Mavrikakis, “Prediction of Experimental Methanol Decomposition Rates on Platinum from First Principles”, Topics in Catalysis (Accepted)
N. Schumacher, A. Boisen, S. Dahl, A. A. Gokhale, S. Kandoi , L. C. Grabow, J. A. Dumesic, M. Mavrikakis, and I. Chorkendorff, “Trends of Low Temperature Water Gas Shift Reactivity on Transition Metals”, Journal of Catalysis, 229 (2005) 265.
A. A. Gokhale, S. Kandoi, J. P. Greeley, M. Mavrikakis, and J. A. Dumesic, “Molecular-level Descriptions of Surface Chemistry in Kinetic Models using Density Functional Theory”, Chemical Engineering Science, 59 (2004) 4679.
S. Kandoi, A. A. Gokhale, L.C. Grabow, J. A. Dumesic, and M. Mavrikakis, “Why Au and Cu are more selective than Pt for preferential oxidation of CO at low temperature”, Catalysis Letters, 93 (2004) 93.
